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Old 02-03-2013, 09:22 PM   #1
dachbach
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Default Starch Conversion but Still Low Mash Efficiency?

I have a couple AG batches under my belt and have been doing tons of research. I have been getting very low efficiencies (50-55%). I recently got my Ward water test and used Bru'n Water to get the right chemicals for my brew (My water had been WAY too alkaline). I was hoping today would be the day it all came together.

I did an iodine test for the first time and I think it showed conversion. I didn't really see any difference in the color of the iodine. If anything it got lighter when mixed with the wort. It definitely didn't turn purple or black. I used my new refractometer for the first time on the first runnings out of the tun and only got 1.065. The table that everyone here references shows that I should have been at a 1.090 for my 1.33 grist ratio. It seems to me that my mash efficiency was only 72% (65/90). Is that right? What should one expect from a mash efficiency? Is this telling me that my crush just isn't good (getting it crushed by the LHBS) or am I not understanding something?

On a further note, according to the Brewer's Friend efficiency calculator, I ended up at only 50% efficiency for what went into the fermenter. Do I suck at sparging too? FYI, I batch sparge and stir the crap out of it before draining.

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Old 02-03-2013, 09:23 PM   #2
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Noob question but could you please provide a link to the table?

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Old 02-03-2013, 09:39 PM   #3
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You can definitely pass the iodine test and get nowhere near full conversion. I recently tested my conversion efficiency using the LHBS crush. At 30 minutes, I had only 83% conversion but no "black". After 60 minutes, I was at 91%. At 90 minutes, I was up to 98%. Iodine is just testing for starch in solution. If it is still locked up inside the grain, iodine won't test for it.


The most likely reason you are getting such low conversion is your crush. If you are getting 50-55% total and only 72% conversion, you are only losing 17-22% in your sparging and dead space. If you were getting 100% conversion, that would equate to upper 70's-low 80's.

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Old 02-03-2013, 09:54 PM   #4
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Eric191312,
Here is one link:
http://www.homebrewtalk.com/images/9/6/3/0/8/first_wort_gravity-57692.gif

I know there is an entire article that goes with it but I can't remember where I found it.

Bill,

I appreciate your answer. Very informative. Am I calculating the efficiency correctly? 65/90 = 72% Do you think a 90 minute mash would do anything for me or do I need to go ahead and get a mill? Is it reasonable to expect 100% from your mash efficiency?

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Old 02-03-2013, 10:00 PM   #5
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Quote:
Originally Posted by dachbach
Eric191312,
Here is one link:
http://www.homebrewtalk.com/images/9/6/3/0/8/first_wort_gravity-57692.gif

I know there is an entire article that goes with it but I can't remember where I found it.

Bill,

I appreciate your answer. Very informative. Am I calculating the efficiency correctly? 65/90 = 72% Do you think a 90 minute mash would do anything for me or do I need to go ahead and get a mill? Is it reasonable to expect 100% from your mash efficiency?
Here it is...footer on the chart was the clue

http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency
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Old 02-04-2013, 12:11 AM   #6
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What was your grain bill, mash water quantity, and sparge water quantity?

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Old 02-04-2013, 12:22 AM   #7
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Yes, you should be able to get pretty darn close to 100% conversion. A finer crush is obviously the simplest way to make sure you do.

If that isn't in the picture right now, you can mash longer, stir more etc. Both of those will help. I'm usually around 75% total efficiency with a 60 minutes mash, but that jumped to 82% in the experiment I did. (Conversion went up 7%, and the total followed) You might want to try it and see how big of a bump you get. Ultimately though, I think addressing the crush is a better long term solution.

The formula above is the approximation. If you follow that braukaiser article, he's got the complete calculations. The chart is also an approximation that assume your grain bill is at 80% fine grind. If you had a lot of specialty grains, your max might be lower. Really though, the approximations are close enough to tell you if you are getting good conversion, and at this point, you aren't.

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Old 03-10-2013, 11:53 PM   #8
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Okay, so I brewed again today and had the exact same thing happen. I got 1.065 for my first runnings and had 1.050 pre-boil for 4.6 gallons. This tells me I got 72% conversion/efficiency from just the mash and 57% efficiency after including sparge. I ended up post boil with 1.056 and 3.75 gallons (52% efficiency).

I've talked to two employees at the LHBS who mill their grains at the LHBS when they brew. One gets a total efficiency of 65% and the other one 77% so they're obviously not having the same conversion problems I'm having.

Could there be something wrong with my mash tun setup that's causing this conversion/efficiency problem? I'm using a cylindrical 5 gallon cooler with stainless steel braid. I'm hitting my temps and I only drop about a degree during the mash. I use two thermometers and they've both been calibrated.

I would be perfectly happy with 65-75% total efficiency but something from my mashing seems to be preventing that.

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Old 03-11-2013, 09:41 AM   #9
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There is obvious some sort of issue w/your process, you should get conversion efficiency above 90%.
If you already didn't be sure to read this:
http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency
http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficien cy

I never struggled with conversion but I found jump in efficiency into the kettle after tightening mill gap, adjusting pH and stirring mash 30 minutes after dough in.
Good luck!

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Old 03-11-2013, 10:33 AM   #10
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Quote:
Originally Posted by dachbach View Post
Okay, so I brewed again today and had the exact same thing happen. I got 1.065 for my first runnings and had 1.050 pre-boil for 4.6 gallons. This tells me I got 72% conversion/efficiency from just the mash and 57% efficiency after including sparge. I ended up post boil with 1.056 and 3.75 gallons (52% efficiency).

I've talked to two employees at the LHBS who mill their grains at the LHBS when they brew. One gets a total efficiency of 65% and the other one 77% so they're obviously not having the same conversion problems I'm having.

Could there be something wrong with my mash tun setup that's causing this conversion/efficiency problem? I'm using a cylindrical 5 gallon cooler with stainless steel braid. I'm hitting my temps and I only drop about a degree during the mash. I use two thermometers and they've both been calibrated.

I would be perfectly happy with 65-75% total efficiency but something from my mashing seems to be preventing that.
Hi dachbach,
I think this will help
As I read this thread, I'm thinking he has a "braid". Switch up to a manifold setup and you will see a significant improvement in your mash efficency.

Anyway, The best setup according to John Palmers book How to brew" http://www.howtobrew.com/appendices/appendixD-1.html
The quadrant circlular design will allow for the best mash efficiency.
My brother made me one of copper and brass. I never get stuck sparges and end up around 82+%.
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